To estimate need for physician manpower in caring for persons aged 65 or older, we have generated two models that focus on the target year 2000. The first provides an overview of medical care of the entire population in this age group and divides care by physician specialty group. The second estimates need for primary care or consultative services of geriatricians based upon designated specialized care. Data for each of these models comes from: 1) secondary analysis of large, population based data sets (e.g., NHIS-SOA, NAMCS); 2) primary data generated by a proposed survey of candidates for the certificate of Added Qualification in Geriatric Medicine and controls; and 3) a Delphi panel of experts in physician manpower. Sensitivity analyses will then be performed to test the influence of possible trends in health care and health status. This proposal seeks funding to conduct the national survey as an essential component of the larger study. The survey will be administered to 1650 physicians to obtain 900 responses, 300 in each of the following groups: 1) Family physician and Internist candidates (both formally trained and self- trained in geriatrics) for certification 2) physicians who expressed interest in the examination but did not apply; 3) control physicians. The instrument will obtain information needed for the models: geographical distribution, profession productivity (both clinical and for non-clinical activities), settings of care, time spent caring for patients of varying complexity and delegation to non-physician providers. These models provide a stable yet flexible mean of estimating manpower for the year 2000 and beyond. The overall study provides methodology that other specialties can adapt to estimate their own manpower needs, generates data that will be important for interagency planning of manpower development, and provide valuable information for implementing manpower legislation in geriatrics.